Electric control system



July 7, 1942. E. PEARsoN 288541 ELECTRIC CONTROL SYSTEM Filed April 12, 1937 Patented July 7, 1942 UNITED STATES PATENT OFFICE 8 Claims.

The present invention relates in general to electric control systems, and more in particular to systems of this character in which means is provided for closing and opening a switch or circuit breaker located at a remote station.

A special object of the invention is to provide new and improved circuit arrangements for controlling automatic loading equipment such as described in my prior Patent No. 2,075,588, whereby said equipment may be cut in or out of service from a distant control station.

A feature of the invention is the provision of supervisory means through the medium of which the operator at the control station may ascertain the position of the switch at the remote station.

The invention is illustrated in the accompanying drawing, which is a conventional diagrammatic circuit drawing of the circuits and equipment involved.

Referring to the drawing, the apparatus at the control station comprises a manually operable key 25 and a battery 23. There is also a meter 10, which functions as an indicator in the supervisory circuit.

At the remote station, which may be a power station, there is provided a polarized relay 34, delayed action relays 43 and 53, a switch 329, solenoids l and 63 for operating the switch, and the battery 39. In case the control system is used in connection with the automatic loading equipment disclosed in my patent previously referred to, the switch 329 controls the connection and disconnection of operating current to such loading equipment whereby it is cut in or out of 329, the operator will throw the key 25 to the left, closing a circuit which extends from ground at 2| by way of meter 10, key contacts 29 and 3D, conductor 24, battery 23, conductor 22, `key contacts 21 and 23, conductor 25, conductor 32, and winding of polarized relay 34 to ground at 33. In response to the closure of the above circuit, relay 34 operates its armature and in such a direction as to close contacts 35 and 36, thereby completing an obvious circuit through the coi] 44 of relay 43.

On energizing, relay 43 closes switches 46 and 41. The closure of the latter switch prepares a circuit for the solenoid '51, which, however, may be neglected for the moment. The closure of switch 46 connects the resistance 50 in parallel with the polarized relay 34 and thus increases the current flow from battery 23 over conductor 29. rIhe increased current ilow is shown on the meter l0 and indicates to the operator that switch 329 is open. If the switch had been closed, the parallel circuit through resistance 59 would not have been closed, due to switch 5| being open, and the meter would not have shown an increased reading.

Having ascertained in the foregoing manner that switch 329 is open, the operator may restore key 25 to normal, whereupon relays 34 and 43 are restored also. If the operator now desires to close switch 329, he will operatekey 25 to the right, thereby closing a circuit extending from ground at 2| by way of meter T5, key contacts 28 and 2l, conductor 22, battery 23, conductor 24, key contacts 30 and 3|, conductor 2|), conductor 32, and winding of relay 34 to ground at 33. The above circuit corresponds to the circuit closed before, when the key was thrown to the left, except that the battery 23 is reversed. Current accordingly flows in the reverse direction through the polarized relay 34, and this relay now operates its armature in the proper direction to close contacts 35 and 31. The closure of these contacts completes a circuit for the coil 54 of relay 53 in an obvious manner, and said relay energizes to close switch 55, preparing a circuit for solenoid 60.

The operator now quickly moves key 25 to its left hand position, thereby again reversing the current flow through the polarized relay 34 and causing said relay to open contacts 35 and 31 and close contacts 35 and 36. As the result of the opening of contacts 35 and 3l the circuit of relay 53 is broken and the relay is deenergized, but the dashpot renders the relay slow-acting and prevents the switch 55 from being opened for an instant. The closure of contacts 35 and 36 completes a circuit for relay 43 as before, and switch 46 is closed to connect resistance 50 in parallel with relay 34. This momentarily produces an increased reading of the meter l5. However, the closure of contacts 35 and 35 also completes the previously prepared circuit for solenoid 59, which energizes, closes the switch 329, and opens the switch 5|. The latter operation opens the parallel circuit through the resistance, which reduces the meter reading to normal, indicating to the operator that switch 329 has been closed. Key may now be restored to normal, whereupon relays 34 and 43, and solenoid 60 are deenergized. The switch 329 remains in closed position after the solenoid 60 has deenergized.

When the operator desires to open the switch 329, he throws the key 25 rst to the left, then to the right, and nally restores it to normal. On operation of the key to the left, relay 34 is energized to close contacts 35 and 36, and relay 43 is energized as previously described, preparing a circuit for solenoid 51 at switch 41. At switch 46 resistance 50 is connected up, but since switch 5l is open the connection of the resistance is without effect. The failure of meter 1I) to show an increased reading advises the operator that switch 329 is closed. When the key 25 is operated to the right, polarized relay 34 reverses its position, breaks contacts 35 and 36, and closes contacts 35 and 31. Coil 44 of relay 43 deenergizes on the opening of contacts 35 and 36, but switch 41 remains closed temporarily due to dashpot 45. When contacts 35 and 31 close, relay 53 energizes, although this is of no interest at this stage. Also a circuit is completed for solenoid 51, which energize's and opens the switch 329. Switch 5| closes at the same time. As the opening of switch 329 and closing of switch 5l take place before the dashpot 45 allows switch 46 to open, the resistance is effectively connected in parallel with relay 34 for a short interval and the meter 10 gives an increased reading, as previously described, to indicate that switch 329 is open. When key 25 is restored, relays 34 and 53 and solenoid 51 are deenergized. The switch 329 re- Y mains in open position.

The invention having been described, that which is believed to be new and for which the protection of Letters Patent is desired will be pointed out in the appended claims.

I claim:

1. In combination, a power switch, a magnet for closing said switch, a magnet for opening said switch, a two-position contact device operable to either position without energizing either of said magnets, means responsive to the operation of said device iirst to one position and then to the other for energizing one of said magnets, and means responsive to the operation of said device to said positions in the reverse order for energizing the other of said magnets.

2. In combination, a power switch, a control line, means for setting up a current flow over said line rst in one direction and then in the opposite direction, means for opening and closing said switch responsive only to current flow over said line in both directions, and means dependent on the direction in which the current ow is first established for determining whether said switch is to be opened or closed.

3, In combination, a power switch, a two-position contact device operable to either position at will, means including a conductor extending to a control station for controlling the operation of said contact device, a magnet for operating said switch, a relay energized responsive to movement of said device to one position, a circuit for said magnet prepared by said relay and completed by said device when the same is moved to its second position, means for delaying the restoration of said relay when said device is moved to its second position, and a switch supervisory circuit controlled by said magnet and including said conductor and a contact of said relay which is held closed until the relay restores.

4. In a control system, a line extending from a remote control station to a power station and there terminating in a polarized relay, a twoposition switch operated by said relay, a slowacting relay energized in one position of said switch, an operating magnet, and a circuit for said magnet prepared by said relay and completed momentarily only upon movement of said switch to the other position, said circuit being broken upon the delayed deenergization of said slow-acting relay responsive to the movement of said switch.

5. In a control system, a polarized relay operated over a conductor extending to a remote station, a second relay energized when said polarized relay is operated in one direction, a supervisory circuit including said conductor completed by said second relay, a switch, a switch control circuit prepared by said second relay, means for delaying the deenergization of said second relay when the said polarized relay is operated in the other direction, and means responsive to the last mentioned operation of said polarized relay for closing said control circuit until the second relay has deenergized.

6. In combination, a power switch, a polarized relay, a conductor extending to a control station, a. variable current responsive indicator at said station, a circuit including said indicator, conductor, and relay in series, means at said station for establishing and reversing the ilow of current over said circuit, means controlled by said relay to open or close said switch responsive to such establishment and reversal of current ow, the switch being opened or closed depending on the direction in which the current flow is rst established, a resistance, and contacts closed in one position of said switch to connect said resistance in parallel with said relay, thereby increasing the current flow in said circuit to control said indicator.

'7. In a control system, two control circuits, a conductor extending to a control station, means at said station for establishing a current flow over said conductor in either direction and for reversing the direction of current flow, and means responsive only to the reversal of current flow within a predetermined time after the cessation of current flow in the direction in which it is rst established for closing one or the other of said control circuits, the circuit which is closed depending on the direction of the current flow before the reversal takes place.

8. In a control system, a control conductor, means at a control station for establishing a current ow over said conductor in either direction at will, a supervisory circuit including said conductor and an indicating device at said control station, a control circuit, means responsive to the establishment of current flow over said conductor in one direction followed by the establishment of current flow in the opposite direction within a predetermined time for closing said control circuit, and means responsive' to the establishment of current flow over said conductor in one direction only for closing said supervisory circuit, whereby said indicating device may be controlled without closing said control circuit.

ERICK PEARSON. 

